Esophageal inflammation disorders such as eosinophilic esophagitis (EoE) characterized by high levels of eosinophils in the esophagus, as well as basal zonal hyperplasia, are gaining increased recognition in children and adults. Many aspects of the disease remain unclear including its etiology, natural history, and optimal therapy. EoE affects all age groups but most frequently individuals between 20 and 50 years of age. Symptoms of EoE often mimic those of gastroesophageal reflux disease (GERD) and include vomiting, dysphagia, pain and food impaction. The common occurrence regarding misdiagnosis of EoE for GERD often results in delayed treatment in patients with EoE. There are currently no approved topically administered anti-inflammatory medications for the treatment of conditions associated with inflammation of the upper portion of the gastrointestinal tract, particularly the inflammatory conditions of the esophagus, i.e., EoE. The disease is painful, leads to difficulty swallowing and predisposes patients to food impaction and other complications. Although systemic treatments with corticosteroids such as prednisolone are effective, they are associated with significant adverse effects such as suppression of the hypothalamo-pituitary-adrenal (HPA) axis as reflected in salivary cortisol levels, generalized suppression of immune function, and particularly in children, troubling side-effects from long term systemic exposure include growth retardation, which may lead to a reduction in adult height.
In contrast, twice-daily treatments of EoE include directing steroid medications through a metered dose inhaler (MDI) to the back of the throat such that they are not appreciably inhaled, and instructing the patient to keep the mouth closed during the “puff and swallow” treatment and rinse the mouth immediately after administration, and not to swallow food or water for two hours after administration. Rinsing is recommended because residual drug in the mouth and throat can lead to candidiasis infection, and swallowing is contraindicated because it may wash drug away from the esophagus. In another study, 50% of fluticasone propionate (FP)-treated patients achieved histologic remission compared with 9% of patients receiving placebo (P=0.047). FP decreased esophageal eosinophil levels, with a more pronounced effect in non-allergic individuals. However, this therapy is particularly problematic for younger children and those with developmental delay, who are unlikely to utilize this puff and swallow technique effectively.
In another randomized, double-blind, placebo-controlled trial performed to evaluate the effect of oral 1 mg budesonide viscous solution (0.5-mg respule dissolved along with five 1-g packets of sucralose in 10-15 mL fluid) dosed twice daily vs. placebo in adolescent and adult patients with active EoE for 15 days, the pretreatment and post treatment disease activities were assessed clinically, endoscopically, and histologically. The primary end point was reduced mean numbers of eosinophils in the esophageal epithelium (number per high-power field [hpf]=esophageal eosinophil load). A 15-day course of treatment with budesonide is well tolerated and highly effective in inducing a histologic and clinical remission in adolescent and adult patients with active EoE. A 35-day course of therapy significantly decreased the number of eosinophils in the esophageal epithelium in patients given budesonide (from 68.2 to 5.5 eosinophils/hpf; P<0.0001); but not in the placebo group (from 62.3 to 56.5 eosinophils/hpf; P=0.48). Dysphagia scores significantly improved among patients given budesonide compared with those given placebo (5.61 vs 2.22; P<0.0001). White exudates and red furrows were reversed in patients given budesonide, based on endoscopy examination. This dosage form has not been FDA approved for commercial use, and the oral administration is going to be messy and likely to produce inconsistent results.
When oral solid dosage forms with a drug load of ≤5% by weight are required, the drug is either micronized and co-processed by blending with at least one carrier excipient or granulating in a fluid bed or high shear granulator by spraying preferably a solution of the drug to achieve blend uniformity/homogeneity of the blend and subsequently, content uniformity in the finished dosage units per regulatory requirements (FDA's Draft Guidance for Industry “Powder blend and finished dosage units—stratified in-process dosage unit sampling and assessment” October 2003). Many micronized drugs show a tendency to segregate and form, larger particles in the blend in order to reduce their high surface energy, resultant segregation and agglomeration could cause resurfacing of the blend non-uniformity/inhomogeneity issues set out to resolve in the first place. Segregation and agglomeration in the blends containing especially poorly water soluble, low-dose drugs must be avoided not only during powder blending but also until processed into finished dosage forms, capsules or tablets, to achieve and maintain desired blend uniformity/homogeneity and/or to avoid high dissolution variability. Segregation of drug particles, especially in direct, compression blends, is equipment and material dependent. It is thus very challenging to achieve acceptable blend homogeneity during direct compression blending of a low-dose drug with suitable pharmaceutically acceptable excipients (i.e., at a drug content of <5% by weight in the blend) and maintain the blend homogeneity until processing into finished dosage forms (e.g., tablets or capsules) (McGinity J. W. et al. Dissolution and uniformity properties of ordered mixes of micronized griseofulvin and a directly compressible excipient. Drug Development and Industrial Pharmacy 1985; 11(4): 891-900; Yalkowsky S. H. and Bolton S. Particle size and content uniformity, Pharmaceutical Research. 1990; 7(9): 962-966; Ahmad H. and Shah N. Formulation of low dose medicines-Theory and Practice. Amer. Pharm. Rev. 2000; 3 (3): 1-5; Mahmoudi Z. N. et al. The influence of filler in blend uniformity of micronized drugs. Contributed poster, AAPS Annual Meeting (USA) 2010; Mahmoudi Z. N. et al. Effect of drug particle size on blend segregation and content uniformity. Contributed poster, AAPS Annual Meeting (USA) 2011).
WO 2011041509 discloses the preparation of an orally administrate pharmaceutical composition containing a topically acting corticosteroid in an amount of less than 20 mg. Although there is no specific discussion of how to achieve acceptable blend uniformity in the working example of the compression blend which contains fluticasone propionate at only 4% by weight, which will be translated into achieving acceptable content uniformity of the ODTs, the fact that fluticasone is granulated with suitable pregranulated excipients, such as rapidly dispersing microgranules comprising mannitol and crospovidone, suggests that the granulation of fluticasone has been performed for the purpose of achieving acceptable content uniformity in the finished tablets. However, the micronized topically acting corticosteroid particles may be present in the agglomerated granules and as such may not be readily exposed to the inflamed EoE tissues upon oral administration for rapid induction of remission of EoE.
There is therefore a need for low-dose corticosteroid compositions having acceptable blend uniformity/homogeneity during blending of a topically acting corticosteroid with suitable pharmaceutically acceptable excipients as a carrier (i.e., at a drug content of <5%, especially at <3% by weight in the blend) and maintain the blend homogeneity until processing into finished unit dosage forms (e.g., tablets or capsules), which while exhibiting high content uniformity are suitable for oral administration in patients to provide topical (rather than systemic) treatment of inflammation of the of the upper gastrointestinal tract, particularly eosinophilic esophagitis (EoE) since the micronized, topically acting corticosteroid particles having been adsorbed largely on the surface of the carrier are capable of rapidly inducing remission of EoE.